Western surveys of idealism have historically overlooked Indian sources as scholars were unfamiliar with Indian metaphysics and lacked appropriate exegetical translations of India’s ancient Sanskrit spiritual literature. But millennia before the (Neo)Platonists conceived their idealist arguments, Indian sages who meditated on causal consciousness produced esoteric teachings, metaphorical descriptions of abstract states, and influential philosophical ideas that shaped the ancient worldview of monistic idealism. Many Indologists argue that the Vedic religion introduced by the prehistorical or ancient Aryan migrants into northern India catalyzed the growth of later Hindu traditions that regard Brahman (Metaseity) as the supreme ontological entity. However, P. R. Sarkar tilts the origins of Indian idealism away from this monolithic Vedic source with his polemical claim that indigenous Śiva Tantra initially existed independently from Aryan Vedic beliefs and propitiatory rites. This essay therefore interrogates the first ancient expression of metaphysics in India through a new translation and reinterpretation of the Ṛg Veda’s canonical “Creation Hymn,” mediated by Sarkar’s Tantric historiography and spiritual metaphysics. By engaging with Sarkar’s emic claim for Tantra’s spiritual and epistemic influences on Vedic thought, I reconstruct the Creation Hymn’s influential monistic ontology to explain its radical departure from the Ṛg Veda’s traditional sacerdotalism. It is proposed that monistic idealism likely originated in India and that the Creation Hymn is the first textual evidence of this philosophy infused with proto-Tantra.